In-line fuse



United States Patent Ofiice 3,280,281 Patented Oct. 18, 1966 3,280,281 IN-LINE FUSE Francis J. Berger, Detroit, Mich, assignor to Essex Wire Corporation, Fort Wayne, Ind., a corporation of Michigan Filed Oct. 19, 1964, Ser. No. 404,798 Claims. (Cl. 200-113) My present invention relates to a simplified and novel in-line fuse designed for use in various types of electrical circuits.

One object of my invention is to provide a new and economically constructed fuse of simple but rugged construction, capable of being easily replaced in a circuit.

Another object of my invention is to provide an improved in-line fuse so designed that melted portions of the fusible elements are spatially separated from proximity to the circuit thus minimizing the chance of resolidification of the melt and accidental closing of the circuit. Still further objects of the invention are particularly lm-portant and include specific details of the novel fuse construction. With these and other objects in view, my invention consists in the construction, arrangement, and combination of the various parts of my in-line fuse, whereby the objects above contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in detail on the accompanying drawing, wherem:

FIG. 1 is .a perspective view of one illustrative embodiment of my in-line fuse;

FIG. 2 is a sectional view taken along line 22 of FIG. 1;

FIG. 3 is a plan view of one type of terminal which may be used in my invention;

FIG. 4 is a plan view of the stretched out fusible element in my invention with its two conductive annuli; and,

FIG. 5 is a side view of 'FIG. 4 showing a hidden line view of the two annuli with connecting fusible element I in looped position as utilized in my invention.

The exemplary embodiment of the invention illustrated in the accompanying drawing comprises a hollow stemmed contact post 2 having a first flanged end 6 and a second flanged end '8. Disposed axially between the said first and second flanges are the conductive annuli ;10 and 14, the fusible element 18, insulating means 30 and '34, and terminal 20, which are hereinafter more particularly described.

Refer-ring to FIGS. '2, 4 and 5 of the drawing it will be seen that the illustrative embodiment of the invention shown comprises a fusible element with a conductive annulus at either end. It will be appreciated by those skilled in the art that this part of the invention can be readily stamped out of tin plate or other suitable conductive material to the required dimensions having in mind the desired capacity of the fuse.

The fuse itself preferably comprises a first conductive annulus '10 with an inner periphery -12 substantially the same size as the external periphery 4 of the contact post 2. The sec-0nd conductive annulus 14 has an inner periphery 16 substantially greater than the external periphery 4 of the contact post 2. Defined on said second annulus '14 are downtur-ned lugs 26 which serve a useful function as hereinafter set out. Conductively connecting said first and second annuli is the fusible element 18 which may be constructed to melt at a predetermined current load.

For insertion into the in-line fuse assembly of the illustrated embodiment, the fuse element shown in FIG. 4 is shaped to substantially conform to the configuration shown by the hidden lines in FIG. '5.

In FIG. :3 is shown one particular type of terminal that is usable in my invention. The terminal 20 is desirably constructed out of steel or some other conductive material and preferably is surface plated with a corrosion resistant material such as cadmium. As illustrated, the terminal 20 has a first hole 22, the diameter of which is substantially greater than the external diameter 4 of the contact post 2. Located in the periphery of said first hole 22 are lug receptacles 28 so disposed as to receive the downturned lugs 26 on the .second annulus '14 when the in line fuse is assembled. The particular terminal 20 shown in FIG. 3 also has a second hole 24 remote from said first hole 22 for receiving a terminal screw or other contact means when the in-line fuse is inserted in an electrical circuit. Obviously the terminal 20 may have various other configurations suitable for use'in my invention.

Shown in the illustrative assembly of FIG. 2 is a first insulating washer 30, and a second insulating washer 34, advantageously made of spauldite or other suitable insulating material. Projecting axially on each insulating washer is a lip, shown respectively as the lips 82 and 36 on the washers 30 and 34 in FIG. 2.

-In the embodiment illustrated in FIG. 1 and FIG. 2, there is a U-shaped metal channel 38 which serves as a rigid backing for said second insulating washer 34 and which may also serve as a bracket for mounting the inventive in line fuse in an electrical circuit.

Having thus described and illustrated the particular components of my in-line fuse, reference is made to FIG. 1 and FIG. 2 to show how these particular components are assembled into my invention. As shown in FIG. 2, the hollow stemmed contact post 2 provides a conductive mounting post on which the various components of my invention are concentrically assembled in compressed arrangement between its first flanged end 6 and its second flanged end 8.

Mounted on the contact post, as show-n in FIG. 2, is the first annulus 10 which is in electrical contact with the contact post 2 at its inner periphery 12 and along the portion where it contacts the first flange 6. This first annulus 10 is connected by the fusible element loop means 18 to the second annulus 14 which has an inner periphery 16 substantially greater than the external periphery 4 of the contact post 2 so that there is radial physical separation of said second annulus 14 from said contact post 2. Filling the space between the contact post 2 and the inner periphery 16 of the second annulus 114 is the axially dependent lip 32 of the washer 30. Axial insulation between said first annulus i10 and said second annulus 14 is accomplished by the first insulating washer 30. Thus an electrical pat-h exists between the first and second annuli only through the fusible element loop K18.

The terminal 20 is positioned on said contact post 2 in electrically conductive engagement with said second annulus 14. The terminal 20 is radially insulated from the contact post 2 by the lips 32 and =36 axially projecting from the insulating washers 30 and =34 respectively. The second insulating washer 34 axially separates and electrically insulates the terminal 20 from the U-shaped channel 38.

The downturned lugs 26 depending from the second annulus 14 are designed to cooperatively engage the lug receptacles 28 on the periphery of the first terminal hole 22 and thus prevent relative movement between said terminal 20 and siad second annulus 14. This assures that the fusible loop element 18 will always be extended in a direction remote from the terminal 20. It will also be understood that the channel or mounting bracket 38 is provided with one or more downturne-d lugs .to enable the fuse to be mounted to a suitable terminal in a manner which prevents turning or rotation of thte fuse during its use.

In production the various components of the in-line fuse may be assembledpon a contact post and thereafter the flanges formed by compressing the ends of said contact post. Other suitable means of production or assembly suggest themselves to those skilled in the art by reference to the drawing and the above description.

As is evident from the drawing, and particularly FIGS. 1 and .2, the in-line fuse may be assembled in a circuit by having a first contact (not shown) depend through the hollow stemmed contact post 2 and having a second contact conductively engage the terminal 20 through the second terminal hole 24. It is further evident that current passing in the circuit through the terminal 20, thence to the contact post 2 and the remainder of the circuit via the U-shaped channel 38 or the second [flange 6 of the contact post, must pass through the fusible element loop means 18. As heretofore discussed, the current carrying characteristics of the fuse may be adjusted by adjusting either the type of metal used in the fuse or the particular dimensions of the fusible loop element, or both.

My novel fuse operates in the well known manner of fuses. Upon a current overload being experienced by said in-line fuse, the fusible loop element 18 will melt at an amperage determined by the current carrying char- .aeteristics of the fusible element.

The novel fuse is so arranged that metal drippings, resulting from the melting of the fusible loop element by an excessive current load, have a free fall path external of the terminal 20 so that resolidification of the molten metal will not result in accidental reclosing of the circuit.

While the invention is susceptible .to various modifications, a preferred embodiment has been shown in the drawing and has been described in considerable detail. It should be understood that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the intention is to cover all modifications and alternative construct-ions falling within the spirit and scope of the invention as expressed in the appended claims.

I claim as my invention:

1. An an-line fuse comprising a contact post having [first and second flanged ends having disposed therebetween a first conductive annulus, a second conductive annulus with a fusible loop element conductively connecting said first and second annuli, a terminal in conductive engagement ,with said second annulus, said terminal having a conductive portion extending upwardly from at least one side of said fuse to enable said fuse to be operatively connected in an electrical circuit, first insulating means spatially separating said first annulus from said second annulus and said second annulus from said contact post, second insulating means spatially separating said terminal from said second flanged end and from said contact post, said contact post being in immediate electrical contact only with said first annulus, and a rigid mounting bracket between said second insulating means and said second flange, said mounting bracket having downturned lug means to facilitate mounting of said fuse to an electrical terminal.

The in-line fuse of claim \1 wherein the said contact post is hollow stemmed.

3. An in-line fuse comprising a contact post having disposed therearound in compressed stacked engagement, a first conductive member in conductive engagement with said contact post, a second conductive member radial-1y insulated from said contact post, first insulating means axially separating said first member from said second member, fusible element means conductively connecting said first member and said second member, a terminal in conductive engagement with said second member and insulated from said contact post, means on said terminal extending outwardly from at least one side of said fuse for operatively connecting said in-line fuse in an electrical circuit and a mounting bracket having angled lug means depending therefrom to enable said fuse to be nonrotatably mounted to an electrical terminal.

4. The in-line fuse of claim 3 wherein the said contact post is hollow stemmed.

5. The in-line fuse of claim 3 wherein said fusible element is arranged to extend outwardly from said fuse in a direction radially spaced from said last-named means to prevent metal drippings resulting from the melting of the fusible element from falling upon said last-named means.

References Cited by the Examiner UNITED STATES PATENTS 2,355,622 8/1944 Brus 20o 13s X 2,811,610 10/1957 Bletz 200-138 BERNARD A. GIL-HEANY, Primary Examiner.

T. D. MACBLAIN, Assistant Examiner. 

3. AN IN-LINE FUSE COMPRISING A CONTACT POST HAVING DISPOSED THEREAROUND IN COMPRESSED STACKED ENGAGEMENT, A FIRST CONDUCTIVE MEMBER IN CONDUCTIVE ENGAGEMENT WITH SAID CONTACT POST, A SECOND CONDUCTIVE MEMBER RADIALLY INSULATED FROM SAID CONTACT POST, FIRST INSULATING MEANS AXIALLY SEPARATING SAID FIRST MEMBER FROM SAID SECOND MEMBER, FUSIBLE ELEMENT MEANS CONDUCTIVELY CONNECTING SAID FIRST MEMBER AND SAID SECOND MEMBER, A TERMINAL IN CONDUCTIVE ENGAGEMENT WITH SAID SECOND MEMBER AND INSULATED FROM SAID CONTACT POST, MEANS ON SAID TERMINAL 